WO 2013/140572 A1 discloses a semiconductor apparatus provided with a plurality of guard rings surrounding a device region where an IGBT (Insulated Gate Bipolar Transistor) is formed. Each guard ring is configured of a p-type region provided in an n-type semiconductor substrate, and is provided at a position exposed in a front surface of the semiconductor substrate. Each guard ring extends in an annular shape surrounding the device region, and the plurality of guard rings surrounds the device region in multiple layers. Further, the semiconductor apparatus includes first peripheral conducting films and second peripheral conducting films. The first peripheral conducting films are provided for each of the guard rings, and each first peripheral conducting film is arranged on the corresponding guard ring via an insulating film. Each first peripheral conducting film extends in an annular shape along the corresponding guard ring, and adjacent first peripheral conducting films are insulated from each other. The second peripheral conducting films are provided for each of the guard rings, and each second peripheral conducting film is arranged on the corresponding first peripheral conducting film via an insulating film. Some of the second peripheral conducting films are provided only at partial positions in a circumferential direction of the first peripheral conducting films. The first peripheral conducting films and the second peripheral conducting films are connected to each other via contact holes provided in the insulating films separating the first peripheral conducting films and the second peripheral conducting films. Further, the second peripheral conducting films and the guard rings are connected to each other by contact holes that penetrate all of the insulating films separating the first peripheral conducting films and the second peripheral conducting films, the first peripheral conducting films themselves, and the insulating films separating the first peripheral conducting films and the guard rings. The second peripheral conducting films are provided to connect the guard ring and the first peripheral conducting film. The first peripheral conducting films function as shielding films suppressing influences of external charges. That is, since a peripheral region is shielded by the first peripheral conducting films, an electric field distribution in the peripheral region is suppressed from being disturbed by an electric field generated by the external charges when the external charges adhere to a front surface of the semiconductor apparatus. A thickness of the second peripheral conducting films is thicker than a thickness of the first peripheral conducting films. A conductive material can be filled in the two types of contact holes upon formation of the thick second peripheral conducting films.
The first peripheral conducting films can be formed accurately due to its thickness being thin. Accordingly, a clearance between the first peripheral conducting films can be made short. By making the clearance between the first peripheral conducting films short, a clearance between the guard rings can be made short as well. On the other hand, the thick second peripheral conducting films have less processing accuracy, so a clearance between the second peripheral conducting films cannot be made short. However, since the second peripheral conducting films are provided at partial positions in the circumferential direction of the first peripheral conducting films, a plurality of second peripheral conducting films can be arranged dispersed in the circumferential direction of the first peripheral conducting films. Accordingly, even if the clearance between the first peripheral conducting film is made short, the second peripheral conducting films are prevented from interfering with each other. By a structure that causes the thin first peripheral conducting films to be electrically connected to the guard rings via the thick second peripheral conducting films, the clearance between the guard rings can be made short without allowing the second peripheral conducting films interfere with each other. Thus, according to this structure, the peripheral region can be made small, and a size of the semiconductor apparatus can be reduced. In the technique of WO 2013/140572 A1, the contact holes connecting the second peripheral conducting films and the guard rings are provided on center lines of the guard rings in a width direction.